diff --git a/akka-stream-tests/src/test/scala/akka/stream/impl/fusing/GraphInterpreterSpecKit.scala b/akka-stream-tests/src/test/scala/akka/stream/impl/fusing/GraphInterpreterSpecKit.scala
index f805a91080..ed423f64ff 100644
--- a/akka-stream-tests/src/test/scala/akka/stream/impl/fusing/GraphInterpreterSpecKit.scala
+++ b/akka-stream-tests/src/test/scala/akka/stream/impl/fusing/GraphInterpreterSpecKit.scala
@@ -299,10 +299,12 @@ trait GraphInterpreterSpecKit extends AkkaSpec {
   }
 
   implicit class ToGraphStage[I, O](stage: Stage[I, O]) {
-    def toGS =
+    def toGS: PushPullGraphStage[Any, Any, Any] = {
+      val s = stage
       new PushPullGraphStage[Any, Any, Any](
-        (_) ⇒ stage.asInstanceOf[Stage[Any, Any]],
+        (_) ⇒ s.asInstanceOf[Stage[Any, Any]],
         Attributes.none)
+    }
   }
 
   abstract class OneBoundedSetup[T](_ops: GraphStageWithMaterializedValue[Shape, Any]*) extends Builder {
diff --git a/akka-stream-tests/src/test/scala/akka/stream/impl/fusing/InterpreterStressSpec.scala b/akka-stream-tests/src/test/scala/akka/stream/impl/fusing/InterpreterStressSpec.scala
index c273912a3c..ef41d96563 100644
--- a/akka-stream-tests/src/test/scala/akka/stream/impl/fusing/InterpreterStressSpec.scala
+++ b/akka-stream-tests/src/test/scala/akka/stream/impl/fusing/InterpreterStressSpec.scala
@@ -16,11 +16,11 @@ class InterpreterStressSpec extends AkkaSpec with GraphInterpreterSpecKit {
   val halfLength = chainLength / 2
   val repetition = 100
 
-  val f = (x: Int) ⇒ x + 1
+  val map = Map((x: Int) ⇒ x + 1, stoppingDecider).toGS
 
   "Interpreter" must {
 
-    "work with a massive chain of maps" in new OneBoundedSetup[Int](Array.fill(chainLength)(Map(f, stoppingDecider))) {
+    "work with a massive chain of maps" in new OneBoundedSetup[Int](Vector.fill(chainLength)(map): _*) {
       lastEvents() should be(Set.empty)
       val tstamp = System.nanoTime()
 
@@ -42,9 +42,10 @@ class InterpreterStressSpec extends AkkaSpec with GraphInterpreterSpecKit {
       info(s"Chain finished in $time seconds ${(chainLength * repetition) / (time * 1000 * 1000)} million maps/s")
     }
 
-    "work with a massive chain of maps with early complete" in new OneBoundedSetup[Int](Vector.fill(halfLength)(Map((x: Int) ⇒ x + 1, stoppingDecider)) ++
-      Seq(Take(repetition / 2)) ++
-      Seq.fill(halfLength)(Map((x: Int) ⇒ x + 1, stoppingDecider))) {
+    "work with a massive chain of maps with early complete" in new OneBoundedSetup[Int](
+      Vector.fill(halfLength)(map) ++
+        Seq(Take(repetition / 2).toGS) ++
+        Vector.fill(halfLength)(map): _*) {
 
       lastEvents() should be(Set.empty)
       val tstamp = System.nanoTime()
@@ -70,7 +71,7 @@ class InterpreterStressSpec extends AkkaSpec with GraphInterpreterSpecKit {
       info(s"Chain finished in $time seconds ${(chainLength * repetition) / (time * 1000 * 1000)} million maps/s")
     }
 
-    "work with a massive chain of takes" in new OneBoundedSetup[Int](Vector.fill(chainLength)(Take(1))) {
+    "work with a massive chain of takes" in new OneBoundedSetup[Int](Vector.fill(chainLength / 10)(Take(1))) {
       lastEvents() should be(Set.empty)
 
       downstream.requestOne()
@@ -99,7 +100,7 @@ class InterpreterStressSpec extends AkkaSpec with GraphInterpreterSpecKit {
 
     }
 
-    "work with a massive chain of conflates by overflowing to the heap" in new OneBoundedSetup[Int](Vector.fill(100000)(Conflate(
+    "work with a massive chain of conflates by overflowing to the heap" in new OneBoundedSetup[Int](Vector.fill(chainLength / 10)(Conflate(
       (in: Int) ⇒ in,
       (agg: Int, in: Int) ⇒ agg + in,
       Supervision.stoppingDecider))) {